Category 4: Sound Transmission and Radiation. Problem 1: Radiation and Refraction of Sound Waves Through a Two-Dimensional Shear Layer

The fourth Computational Aeroacoustics (CAA) workshop emphasized the application of CAA methods to the solution of realistic problems. Workshop participants presented their solutions to problems in one or more of five categories along with the comparisons of their solutions to the benchmark solutions or experimental data.This report is concerned with Category 4:Sound Transmission and Radiation.The first problem in this category is to compute the sound transmitted through a turbulent shear layer without triggering a possible instability wave that may form part of the solution. The problem consists of an energy source inside a two-dimensional jet that generates an acoustic wave that is refracted as it moves through the jet shear layer. The benchmark problem requires the solution of the two-dimensional linearized Euler equations to calculate the .uctuations associated with only the sound radiation and refraction through the jet. The locations of the required output data and its format are given below. The numerical solutions will be evaluated by comparison with an exact analytical solution.The second problem involves computing the interaction of a given sound source with a computed laminar shear flow. The solution to this problem is numerical with the initial benchmark solution computed by Barone and Lele.